2015-03-03T18:48:27ZSelected road condition, vehicle and freight considerations in pavement life cycle assessmenthttp://hdl.handle.net/10204/7845
Title: Selected road condition, vehicle and freight considerations in pavement life cycle assessment
Authors: Steyn, WJ vdM; Nokes, W; Du Plessis, L; Agacer, R; Burmas, N; Holland, TJ; Popescu, L
Abstract: Road condition affects the operations and costs of vehicles using the infrastructure, as well as the rate at which the road deteriorates during use. Therefore, active and timely management of the road condition can be used as a tool to extend the service life of a road. One of the objectives of pavement Life-Cycle Assessment (LCA) is to evaluate the consequences of changes to a system on the entire life cycle and thus all relevant issues that may affect the operation of the system. It provides a comprehensive approach to evaluating the total environmental burden of a road, examining all the inputs and outputs, including material production, road construction, road use, maintenance and rehabilitation and end of life phases for road infrastructure. This paper focuses on issues that are directly affected by the road riding quality, and how this can potentially be utilized in LCA. The paper is mainly based on a pilot study conducted for the California Department of Transportation (Caltrans) where actual road condition data from two corridors were collected and analyzed to determine the effect of the current road condition and potential changes in these road conditions on the economic and environmental impacts of the situation. Existing Vehicle Operating Cost (VOC) and environmental models were used for the analyses, and new relationships developed for potential freight damage. The objective of the paper is to demonstrate the importance of incorporating the active management of road condition as an aspect of LCA.
Description: International Symposium on Pavement Life Cycle Assessment, Davis, CA, USA, 14-16 October 20142014-10-01T00:00:00ZPermanent deformation behavior of naturally occurring bituminous sandshttp://hdl.handle.net/10204/7803
Title: Permanent deformation behavior of naturally occurring bituminous sands
Authors: Anochie-Boateng, J; Tutumluer, E; Carpenter, SH
Abstract: Oil sand, or tar sand, is a generic name given to bituminous sand deposits that are rich in bitumen or asphalt content to the extent that oil can be extracted from these deposits. The typical 8% to 15% presence of bitumen in the soil composition makes these naturally occurring sands low load-bearing materials. In this study, repeated load triaxial tests were conducted on three types of oil sand materials with natural bitumen contents of 8.5%, 13.3%, and 14.5% by weight. The oil sand specimens were compacted close to field densities and then tested for permanent deformation at two temperatures using a newly proposed test procedure. The procedure applied stress states and ratios determined from field-loading characteristics of haul trucks and mining equipment at two different load pulse durations or loading frequencies (related to field-trafficking speeds). Both the test data and axial permanent strain models developed in the form of power functions of the number of repeated load applications indicated a strong dependency of oil sand permanent strain development on the applied vertical to horizontal (or major to minor principal) stress ratio. Using the test data, permanent strain and deformation models were developed with high correlation coefficients to account for the applied stress states and ratios, test temperature, and bitumen content. These models generalized for oil sand deformation behavior may be used as practical predictive equations to estimate the amount of rutting in oil sand materials and to alleviate potential sinkage problems faced by off-road haul trucks, shovels, and other mining equipment in the field.
Description: Copyright: 2008 National Academy of Sciences. Published in Journal of the Transportation Research Board, vol. 2059, pp 31-402008-01-01T00:00:00ZUltra-thin reinforced concrete pavements (UTRCP): Addressing the design issueshttp://hdl.handle.net/10204/7789
Title: Ultra-thin reinforced concrete pavements (UTRCP): Addressing the design issues
Authors: Du Plessis, L; Kilian, A; Mngaza, K
Abstract: The design and use of ultra-thin reinforced concrete pavements (UTRCP) are well known and are implemented successfully in residential streets and low-volume roads. Various publications are available to assist engineers and contractors to successfully design and construct roads using this labour-intensive construction technique. The current structural design of UTRCP is for low-volume road applications with a total expected traffic of less than 1 million equivalent single 80 kN axle loads. This paper deals with an analytical evaluation based on laboratory results and computer modeling to determine the stress condition under loading and to determine the design life of the UTRCP pavement system under various loading states. The paper includes a critical review on previous published CBR cover curve design charts for UTRCP pavements.
Description: The 33rd Annual Southern African Transport Conference, CSIR ICC, Pretoria, South Africa, 7 - 10 July 2014.2014-07-01T00:00:00ZA case study of intelligent compaction used in road upgradeshttp://hdl.handle.net/10204/7788
Title: A case study of intelligent compaction used in road upgrades
Authors: Leyland, R
Abstract: Compaction is one of the more important processes in roadway construction. It is needed to achieve high quality and uniformity of materials and ensure design performance. Current procedures using conventional compaction machines and limited Quality Control/Quality Assurance procedures may result in inadequate and/or non-uniform material densities, which can be one of the major factors that result in premature pavement failure. One of the most recent advances in related technology is that of intelligent compaction (IC) systems. As a whole such systems are said to provide numerous advantages including increased productivity, proactive compaction process adjustment, reduced spatial variations in compaction and greater data coverage compared to traditional testing methods. In a field study numerous different IC systems where used during construction of a number of experimental road sections in South Africa. These sections formed part of a road upgrade project typical of most road construction projects currently being performed in South Africa and the results obtained highlight the advantages and disadvantages of using the systems on such sites. Advantages included those commonly listed in IC literature whereas the disadvantages were related to the depth of measurement and manmade (brownfield) geological complexities. From this project potential advances in IC systems as well as additional uses of IC as a shallow subsurface characterization tool have been proposed.
Description: Copyright: Springer International Publishing, Switzerland. Abstract only.2014-08-01T00:00:00Z